docs: def preferences(self, section=None):
          """
          Return a list of all registered preferences
          or a list of preferences registered for a given section
  
          :param section: The section name under which the preference is registered
          :type section: str.
          :return: a list of :py:class:`prefs.BasePreference` instances
          """
  
          if section is None:
              return [self[section][name] for section in self for name in self[section]]
          else:
              return [self[section][name] for name in self[section]]